CN101673319B

CN101673319B - Method for assessing steel structural building after fire hazard

Info

Publication number: CN101673319B
Application number: CN2008100428911A
Authority: CN
Inventors: 包朝亮; 罗永峰; 张立华; 赵智勇; 王秋蓉; 薛奡; 余加坤; 胡邦盛
Original assignee: Shanghai Baoye Engineering Technology Co Ltd
Current assignee: Shanghai Baoye Engineering Technology Co Ltd
Priority date: 2008-09-12
Filing date: 2008-09-12
Publication date: 2011-10-05
Anticipated expiration: 2028-09-12
Also published as: CN101673319A

Abstract

The invention belongs to a method for assessing building structures under specific conditions, and particularly relates to a method for assessing a building structure after fire hazard. The method for assessing the steel structural building after fire hazard is characterized by comprising the main working procedures of (1) detection scheme determination according to field investigation, (2) detection and test, (3) data processing structure analysis, (4) reliability assessment detection and expert conclusion, and (5) conclusion and treatment suggestion. By combining the characteristics that the material quality and the integral stability of a steel structural member after the fire hazard are changed, the invention establishes and provides a scientific and objective method for detecting and assessing the steel structural building after the fire hazard, which provides basis for the bearing capacity assessment, structure reinforcement and building use safety for the building structural member after the hazards.

Description

The assessment method of steel structural building after fire hazard

(1) technical field

The invention belongs to building structure a kind of assessment method under given conditions, particularly relate to a kind of assessment method of building structure after being subjected to fire.

(2) background technology

According to the United Nations " World Fire Statistics Centre ", more than 10,000 of whole world breaking out of fire every day, the hundreds of people of fire fatality number.In China, about 40,000 of annual breaking out of fire, dead people more than 2000, hinder 3000-4000 people, up to a hundred houses are because fire is impaired even cave in, the direct property loss that annual fire causes reaches more than 10 hundred million yuan, and the especially big malignant fire of tens people, hundreds of people's death also happens occasionally, and brings about great losses for the country and people's lives and properties.After buildings suffers fire, structure and member will be subjected to damage or destruction in various degree, sometimes even can cause the inefficacy of total or the destruction of collapsing.Building structure could continue to use behind fire, the rescue personnel enters disaster-stricken scene and carries out whether safety of rescue work after calamity, all depend on the stress performance of damaged building structure after the calamity and the bearing safety of structure, thereby, the study on assessing method of the damage check of structure and member and assessment method and damaged structure or component load-bearing ability after the calamity is one of important content in the modern state disaster prevention and control strategy.

Although the detection case history of structural elements damage after detection method after the existing at present multiple steel structure member damaged and the calamity, and existing related specifications standard is just done one to the detection of existing steel building and evaluation and is generally illustrated, but after steel building is subjected to high temperature of fire, its degree of impairment has specific characteristics, and the synthetic study of the check and analysis of damaged structural system and Bearing Capacity Evaluation method still belongs to blank at home and abroad.Therefore, be badly in need of a kind of assessment method is provided so that science, take some countermeasures economically.

(3) summary of the invention

The objective of the invention is the characteristics that changed by fire back material and resistance to overturning in conjunction with steel structure member, set up a kind of science, the objectively detection and the assessment method of steel structural building after fire hazard, for load-bearing capacity assessment, the structural strengthening of building structural element after the calamity and the security that buildings is used provide theoretical foundation.

Purpose of the present invention is realized by following technical scheme.

The assessment method of steel structural building after fire hazard is characterized in that, described method comprises following groundwork program:

1. field investigation determine the detection scheme program, 2. detect test routine, 3. the data processing structure routine analyzer, 4. reliability assessment detects and expert's conclusion program and 5. conclusion and handle recommended procedure.

Described field investigation determines that the detection scheme program is:

A) consult fire report, understand cause, position, combustion process and time, extinguishing method and the means of fire, determine disaster-stricken scope;

B) investigate fiery load, constructure ventilation condition, search temperature and judge evidence, tentatively infer Temperature Distribution;

C) consult former design drawing, delivery receiving acceptance record, structure use data and other associated documents, and check, determine structural damage situation and destructive characteristics, divide impairment scale, and judge component damage and hazard level with the practical structures situation;

D) formulate and to reconnoitre detection scheme, consult and study associated documents, made by the version of fiery buildings can to find out building be subjected to the detection scheme of reconnoitring of fire back damage location and degree at each;

E) consult fire attack and fire investigation report,, judge fire scene temperature and reach by scene of a fire residue, structure external appearance characteristic;

F) fiery load, ventilation condition temperature field calculating parameters needed and boundary condition are determined in investigation, carry out the fire scene temperature analytical calculation, draw fire process temperature curve and maximum temperature distribution plan.

Described detection test routine is:

A) structural entity behind the fire and member are checked and detected, comprise that steel structure member fireproof jointing sheath and surface color thereof, malformation, node connect damage, draw the damage distribution plan;

B) to being subjected to fiery member to carry out structured material metal lographic examination, chemical constitution check and mechanical properties test;

C) steel deformation of members damage after employing dimensional measurement method measurement, the non destructive detection mothod detection of fires;

D) according to fiery density of load, combustible characteristic, be subjected to thermal conduction characteristic, ventilation condition and the fire extinguishing procedure of fiery space envelope wall, infer and adopt fire disaster simulation software to carry out numerical simulation and determine the fire scene temperature process by combustion law;

E) infer operative temperature, duration and the distribution range of fire according to structure apparent situation, scene of a fire residue situation and combustible characteristic, ventilation condition, the analysis of fire attack process synthesis, infer according to structured material micro-analysis result for important scaling loss structure to structure; Infer temperature and the reach that component surface once reached according to scene of a fire residue fusing, distortion, burning, scaling loss degree;

F) infer the temperature that steel component inside cross section once reached behind the fire according to fire scene temperature process, steel member flameproof protection degree and flameproof protection material behavior by heat transfer theory and numerical method;

G) determine to be subjected to fiery construction material service check by on-site sampling test or the steel of the same race cooling test of heating.

Described data processing structure routine analyzer is:

A) the structure fire-response analysis comprises structural response analysis in the fire process and the structural response analysis behind the fire; During according to fire action on the steel construction combination of actual loading carry out structure analysis in the fire process, carry out structure analysis behind the fire according to the steel structure material mechanical property behind the fire, connection status, geometrical shapes variation and deformation of members and damage;

B) numerical simulator of using the steel construction fire performance carries out structural-load-carrying capacity calculating, and wherein established model calculates according to structure and is subjected to fire back present situation.

Described reliability assessment detects with the evaluation program conclusion:

According to the every testing result of steel structure member behind the fire, crack defect, metallographic testing result, propose to do focus efforts on special areas and/or technical finesse and/or continue to use suggestion to member.

Described conclusion and recommended procedure are:

According to detecting assessment result,, propose: have a strong impact on suggestion and remove replacing in conjunction with the actual conditions of engineering; Substantially not having influence suggestion reinforcement and strengthening handles; Do not exceed permissible value with distortion, the crack defect vestige is not found in flaw detection, metallographic no abnormality seen phenomenon, the conclusion that can continue to use and processing suggestion.

Superiority of the present invention and beneficial effect, the characteristics that changed by fire back material and resistance to overturning in conjunction with steel structure member of the present invention, set up and provide the detection and the assessment method of a kind of science, objective comprehensive steel structural building after fire hazard, for load-bearing capacity assessment, the structural strengthening of building structural element after the calamity and the security that buildings is used provide theoretical foundation.

Assessment through multinomial embodiment, disaster-stricken steel building is taked different treatment Countermeasures, and the maintenance and repair expense has been saved in the loss of both having avoided buildings simply to scrap again pointedly, also can avoid blindly utilizing the security incident that causes, economic worth and social benefit are obvious.

(4) description of drawings

Fig. 1 is subjected to fiery steel member synoptic diagram for 106 meters platforms of assessment method one embodiment of steel structural building after fire hazard of the present invention;

Fig. 2 is that 106 meters platforms are subjected to fiery steel member synoptic diagram;

Fig. 3 is 94 meters---106 meters platforms are subjected to fiery steel member synoptic diagram;

Fig. 4 is the degenerated curve of the strength of materials under the high temperature;

Fig. 5 is 19 layers 94.5 meters 19L-6 web defect map.

(5) specific implementation method

Further specify technical solution of the present invention below in conjunction with accompanying drawing.Detection and the evaluation of embodiment after for certain ironmaking tower 20 layers of framework steel construction fire.

Certain ironmaking tower belongs to 20 layers of framework steel structural form, and this project design life is 50 years, and seismic fortification intensity is 7 degree, and designing basic seismic acceleration is 0.1g.This tower framework steel construction adopts Q345C, Q345B and Q235B structural section.

This engineering bolt is high-strength bolt, connects rubbing surface and adopts sand-blast to handle, and has adopted wire brush to remove floating rust during installation.The equal equal strength splicing of all members, the steel member all adopts sandblast or impeller cleaning to handle, and all steel plate normalizings are supplied and through ultrasonic testing, are reached 2 grade standards.The butt-weld of all through weldings meets the requirement of second-order weld, and factory's butt-weld that connects material meets the requirement of first-order weld, and fillet weld meets the requirement of three grades of weld seams.

Component surface does not have designing requirement to frie retardant coating, and priming paint adopts C53-31 lead red alcohol acid antirust paint, two times 50～60 μ m; Intermediate coat adopts C53-34 cloud iron alcohol acid antirust paint, one time 25～30 μ m; Finish paint adopts C04-42 synthetic enamel, three times 65～80 μ m.The finish paint color adopts the candle light orchid.In order to prevent erosion rust in the installation process, priming paint has only been brushed in the capable post of case inside, and all members are not coated with frie retardant coating.

1. the detection scheme program is determined in field investigation

Scene of fire investigation record

Reflect that according to the field staff this fire betides about 9 of mornings in such a month, and on such a day, 2007, immediately report to the police, puted out a fire to save life and property flame-out by fire brigade about 10: 30 morning, the same day, weather was clear to cloudy, 4～5 grades of northeasters, vertical strap transporter and relevant device burn fully, owing to the intensity of a fire does not thoroughly spread to periphery, so framed structure is subjected to the serious zone of fire to be positioned at the 94.5m platform of structural tower southwest corner to 106m framed structure part.

This project vertical strap transporter casing deformation is serious, and surface irregularity, paint basic burning the in fire lost, part from burning things which may cause a fire disaster far general plan leave paint.Surveyed area is impaired serious slightly with the outer fence surface, is darkened with smoke serious position peeling paint near steel component surface such as burning things which may cause a fire disaster place beam, posts.90m platform vertical strap conveyor belt is burnt fully, and vertical strap transporter shell is broken.90m platform post, support and node surface sooting are also bubbled.94.5m platform bottom girder, secondary beam are serious through the visual inspection scaling loss, part girder color is burnt to being brown white.It is serious to observe 94 meters to 106 meters frame beam column damages through outward appearance, and burn to being brown white many places.

Sensing range

This surveyed area is a vertical axis 71.5～85.0, axis of pitch C/100.0～C/109.5, absolute altitude is a steel construction part between+90～+ 106 meters, the main post that detects two-layer platform burn serious (color is burnt to white), girder, (the member numbering is seen Fig. 1 to the diagonal brace that is connected with the beam column of encorbelmenting, Fig. 2, Fig. 3,20L-1 wherein, 20L-2 represents that the 90m platform is to 106m framed structure part studding, 20V-1,20V-2 represents that 94.5m platform place tiltedly draws 2 supports of outrigger platform, 19V-1,19V-2,19V-3,19V-4 represents to be positioned at 4 supports of intercolumniation at 90.5m platform place).

Carry out the fire scene temperature analytical calculation when having ready conditions, draw fire process temperature curve and maximum temperature distribution plan.

2. detect test routine

Detected by the measure of fiery regional steel structure member flameproof protection

Because this project steel structure member does not all have the frie retardant coating requirement, so the scene mainly is subjected to the surperficial paint of fiery regional steel structure member to be subjected to fire back dropping situations and change color to judge that steel structure member is subjected to the fire time to reach the highest fiery temperature that is subjected to by range estimation.

Be subjected to fiery regional steel structure member deformation detection

Steel structure column is tilted and deformation measurement, steel structure girder is carried out amount of deflection and deformation measurement, measuring method all adopts no prismatic reflection total powerstation to measure, and test item is mainly based on amount of deflection.

Be subjected to fiery steel construction test specimen surface inspection

Adopt painted or magnetic powder inspection method, the steel member of serious to damaging (color is burnt to white) carries out comprehensive surface inspection, comprises fillet weld and mother metal, and the steel member of serious (color is burnt to black) carries out the face of weld flaw detection to damaging.

Be subjected to fiery regional steel, weld seam metallographic examination

Adopt the method for multiple film that steel, weld seam are carried out metallographic examination; The steel member of serious to damaging (color is burnt to white) carries out mother metal and weld seam carries out metallographic examination, and each steel member weld seam is provided with that one meter of two check point, mother metal are provided with a check point, hardness test is that above each measuring point is surveyed five hardness test points; The steel member of serious (color is burnt to black) carries out weld seam metallographic examination and hardness test to damaging, and the weld seam test point is with identical with upper member weld seam layout.Stay bolt is carried out comprehensive metallographic examination and hardness test.Available in case of necessity simulated combustion test is determined.

3. data processing structure routine analyzer

Determined by the serious steel member temperature field of fire

Owing to there are not effective ways determined by fire back cross-section temperature field at present to the steel member, so the scene is watched through having gone the steel component surface, be subjected to fire back dropping situations and change color to judge that steel structure member is subjected to the fire time to reach the highest fiery temperature that is subjected to according to component surface paint.According to relevant testing data, ordinary steel is about 540 ℃ in the critical temperature that loses static balancing stability under the full-power situation.Generally when (300～400) ℃, its intensity begins to descend; To about 600 ℃, the mechanical property of its steel all descends rapidly such as yield point, compressive strength, elastic modulus and weight bearing power etc., is lower than the desired yield strength of building structure, just is lower than the carrying permissible stress of building structure.

Under short-term high temperature (such as fire), the yield strength of common iron commonly used thinks constant at 200 ℃ with interior being similar to, 40% when being about its normal temperature in the time of 550 ℃ in the building; Use for tendon high-strength steel offset yield strength raises and will reduce gradually with temperature, 40% when being about its normal temperature during to 400 ℃, as shown in Figure 4.The temperature that common iron experienced is recovered substantially 600 ℃ of following mechanical properties; The temperature that the use for tendon high-strength steel is experienced is below 400 ℃ the time, and the interior mechanics performance can be recovered mostly behind the high temperature, experiences intensity behind 600 ℃ of high temperature and can return to about 60% before impaired.

Check that steel component surface and temperature field analysis the results are shown in Table 1.

Table 1

Sequence number number	Element type and structure piece number	The component surface color of paint	Be subjected to fiery temperature	Be subjected to the fire time (approximately)
					1	Girder 19L-1	Brown white	<500℃	30 minutes
2	Secondary beam 19L-2	Brown white	<500℃	30 minutes
					3	Secondary beam 19L-3	Brown white	<500℃	30 minutes
4	Secondary beam 19L-4	Brown white	<500℃	30 minutes
					5	Secondary beam 19L-5	Brown white	<500℃	30 minutes

6	Girder 19L-6	Brown white	<500℃	30 minutes
					7	Girder 19L-7	Brown white	<500℃	30 minutes
8	Girder 19L-8	Brown white	<500℃	30 minutes
					9	Girder 19L-9	Brown white	<500℃	30 minutes
10	Secondary beam 19L-10	Brown white	<500℃	30 minutes
					11	Secondary beam 19L-11	Brown white	<500℃	30 minutes
12	Tiltedly draw 20V-1	Brown white	<500℃	30 minutes
					13	Tiltedly draw 20V-2	Brown white	<500℃	30 minutes
14	Girder 20L-1	Brown white+light brown	<400℃	20 minutes
					15	Girder 20L-2	Brown white+light brown	<400℃	20 minutes
16	Girder 20L-3	Brown white+light brown	<400℃	20 minutes
					17	Girder 20L-4	Light brown	<300℃	15 minutes
18	Girder 20L-5	Light brown	<300℃	15 minutes
					19	Post 20Z-1	Sooty black+light brown	200℃～300℃	20 minutes
20	Post 20Z-2	Sooty black+light brown	200℃～300℃	20 minutes
					21	Tiltedly draw 19V-1	Sooty black	200℃	10 minutes
22	Tiltedly draw 19V-2	Sooty black	200℃	10 minutes
					23	Tiltedly draw 19V-3	Sooty black	200℃	10 minutes
24	Tiltedly draw 19V-4	Sooty black	200℃	10 minutes

Illustrate: the steel member rear surface of overdoing is 4 kinds of color and lusters, is respectively paint look, sooty black, light brown, brown white, and according to test experience after the calamity, the paint color temperature generally is not subjected to temperatures involved, does not overdo substantially, and the steel component strength is not affected; The sooty black degree that generally overdoes is lighter, can think the sootiness vestige; Light brown lighter than brown white burn degree, heavier than sooty black burn degree, its intensity begins slightly to descend, but does not influence load-bearing capacity and functions of use; Brown white is for being subjected to fiery degree the heaviest, and under non-damaged situation about detecting, whether the functions of use of its steel influenced also need detect a flaw, metallographic, distortion etc. further detect and identify.

In the steel structure member that this emphasis detects, 94m platform institute detection means all is brown white substantially, and 106m framed structure part 20L-1,20L-2,20L-3 beam are divided into brown white near southwestern sidepiece, and all the other are light brown substantially, and post 20Z-1 is a sooty black.

Checked by the serious steel scantling of fire

(steel tape model 3m) carried out checking to steel member section size in the scene, on-the-spot testing result shows: each beam column does not all have obvious bending deformation situation in the surveyed area, beam, post scantling deviate-8mm～+ 2mm, also substantially in the size allowed band of " code for acceptance of construction quality of steel structures " regulation.

The steel construction amount of deflection detects and analyzes

The testing staff uses come card TCR1202R300 high precision total station that members such as surveyed area beam column have been carried out the amount of deflection detection, and testing result sees Table 2:

Amount of deflection testing result table table 2

Sequence number number

The structure piece number

Actual measurement maximum immunity value (mm)

I level amount of deflection permissible value (mm)

II level amount of deflection permissible value (mm)

III level amount of deflection permissible value (mm)

The distortion grading

Remarks

1

Beam 19L-1

8

<23.75

23.75～47.5

>47.5

|

Be the non-damage distortion, function does not have influence

2

Beam 19L-2

21

<17.6

17.6～35.2

>35.2

||

The distortion of one side is less, but opposite side is subjected to the fire distortion bigger, is subjected to the effect of contraction of 19L-9 beam, produces influential than the large deformation function

3

Beam 19L-3

22

<17.6

17.6～35.2

>35.2

||

Function is influential

4

Beam 19L-4

7

<12

12～24

>24

|

Function does not have influence

5

Beam 19L-5

12

<12

12～24

>24

||

Function does not have influence

6

Beam 19L-6

7

<13.75

13.75～27.5

>27.5

|

Function does not have influence

7

Beam 19L-7

5

<13.75

13.75～27.5

>27.5

|

Function does not have influence

8

Beam 19L-10

16

<11.75

11.75～23.5

>23.5

||

Function is influential

9

Beam 20L-2

11

<20

20～40

>40

|

Function does not have influence

10

Beam 20L-3

12

<30

30～60

>60

|

Function does not have influence

11

Beam 20L-4

7

<19.5

19.5～39

>39

|

Function does not have influence

12

Beam 20L-5

7

<19.5

19.5～39

>39

|

Function does not have influence

13

Post 20Z-1

10

<26.5

26.5～53

>53

|

Function does not have influence

Illustrate: its middle girder amount of deflection maximum permissible value is lo/400, and lo is an effective span, and inferior beam deflection maximum permissible value is lo/250, and post amount of deflection maximum permissible value is for being H/1000, and H is the post height overall.

On-the-spot testing result shows that being subjected to the more serious zone of fire is axis of pitch C/109.5～C/100, and wherein, beam 19L-2,19L-3,19L-10,19L-11 are out of shape bigger, exceed the size allowed band of defined.

Be subjected to serious steel member carrying out flaw detection of fire and analysis

Steel construction is subjected to the serious position of fire after grinder buffing, DPT-8 infiltration, cleaning, developing are handled, this project the 19th layer (94.5m), the 20th layer of (106m) framed structure part girder steel mother metal and face of weld are carried out PT to be detected, the result finds that on the 19th layer of (94.5m) platform 19L-6 steel beam web plate 8 place's crack defect vestiges show, detect signal as Fig. 5.

According to JB/T6062-92 " Steel Structure Weld penetrating inspection method " standard rating, the 19L-6 girder steel is defective.

Be subjected to the serious steel member metallographic examination of fire

The multiple film metal lographic examination in scene is carried out to 94.5 meters platforms and 106 meters platform steel constructions respectively in the scene, and assay is as follows:

94.5 meters platform steel members are detected

(1) get 7 place's mother metals (being numbered 19L-1-1 ~ 8) and place's weld seam (numbering 19L-1-5) on the 19L-1 altogether, the mother metal tissue is ferrite+pearlite, and grain size is about 8 grades.Commissure mother metal microstructure is ferrite+pearlite, the phase transformation annealed zone is thin ferrite+pearlite, and the overheated zone is thick acicular ferrite (Widmannstatten structure)+sorbite, and metal grain is very thick near the fusion area, tissue odds is even, mainly is Widmannstatten structure+sorbite.The weld seam microstructure mainly is thick ferrite+granular bainite.The no abnormality seen tissue.19L-7,19L-8,19L-9 sampling point are mother metal, and tissue is ferrite+pearlite, and grain size is about 8 grades, the no abnormality seen tissue.

(2) find crackle on the 19L-6 web mother metal, the crackle broad, difficulty is distinguished crackle character, the decarburization of cracks mother metal organizes crystal grain thick, near the serious nodularization of position mother metal pearlite.

(3) 19L-2,19L-3,19L-4 mother metal organize medium pearlite to have spherodization.

106 meters framework steel members are detected

(1) 20Z-1 gets two place's mother metals (20Z-1-1,20Z-1-2) and place's weld seam (20Z-3) altogether, and mother metal is organized as ferrite+pearlite, and grain size is 8 grades.The commissure mother metal is organized as ferrite+pearlite, and seam organization is ferrite net+sorbite, no abnormality seen.

(2) totally 5 beam sampling points are all on mother metal in 20L-1 ~ 5, and the check back is found to organize all normal, and not seeing has overheated and burning phenomenon.

From this metal lographic examination result, on 94.5 meters platforms, except girder (19L-2 ~ 5) existing problems of 19L-6 and centre, other positions are organized all normal.106 meters framed structure parts, pillar and five beams are organized all normal.

(3) everywhere hardness number all in normal range.

4. reliability assessment detects and the expert's conclusion program

Steel member reliability assessment table 3 behind the fire

Illustrate: the I level is defective and the damage that member normally, does not reduce the load-bearing capacity and the refractability of member in the comprehensive evaluation; The II level is qualified, does not have obviously to reduce the defective and the damage of component load-bearing ability, but may cause the reduction of permanance; The III level is defective, has produced the defective and the damage that have a strong impact on component load-bearing ability and permanance.

5. conclusion and handle recommended procedure

Conclusion

Find according to the every testing result of steel structure member behind this fire, beam 19L-2,19L-3,19L-10,19L-11 are out of shape bigger, on the 19th layer of (94.5m) platform 19L-6 steel beam web plate, find 8 place's crack defects, on 94.5 meters platforms, except secondary beam (19L-2,19L-3,19L-4,19L-5) the metallographic testing result existing problems of 19L-6 and centre, other positions are organized all normal.Assessment by analysis is subjected to fire to influence more serious partial component need to do focus efforts on special areas and technical finesse to above, and the member that other damage is slighter can continue to use.

Handle suggestion

According to detecting assessment result, in conjunction with the actual conditions of engineering, the treatment measures suggestion is as follows:

(1) the 19L-6 girder is found through flaw detection, and 8 place's crack defect vestiges are arranged on the web, and rating is the IV level, and structure also exceeds standard, and its load-bearing capacity and permanance have produced and had a strong impact on, and suggestion is removed and changed.

(2) secondary beam 19L-2,19L-3,19L-4,19L-5 distortion is bigger, and the metal lographic examination result also exceeds standard, and replacing is removed in suggestion.

(3) secondary beam 19L-10,19L-11 distortion is bigger, but all other testing results all comply with the national standard requirements, and its load-bearing capacity does not have influence substantially, but may cause that permanance reduces, so the processing of suggestion reinforcement and strengthening.

(4) beam 19L-1,19L-7,19L-8,19L-9,20L-1,20L-2,20L-3,20L-4,20L-5, post 20Z-1,20Z-2, diagonal brace 20V-1,20V-2,19V-1,19V-2,19V-3,19V-4 distortion do not exceed the permissible value of national regulation, the crack defect vestige is not found in flaw detection, metallographic no abnormality seen phenomenon can continue to use.

The characteristics that changed by fire back material and resistance to overturning in conjunction with steel structure member of the present invention, set up and provide a kind of science, the objectively detection and the assessment method of steel structural building after fire hazard, for load-bearing capacity assessment, the structural strengthening of building structural element after the calamity and the security that buildings is used provide theoretical foundation.

Claims

1. the assessment method of steel structural building after fire hazard is characterized in that, described method comprises following groundwork program:

1. field investigation determine the detection scheme program, 2. detect test routine, 3. the data processing structure routine analyzer, 4. reliability assessment detects and expert's conclusion program and 5. conclusion and handle recommended procedure;

Described field investigation determines that the detection scheme program is:

F) fiery load, ventilation condition temperature field calculating parameters needed and boundary condition are determined in investigation, carry out the fire scene temperature analytical calculation, draw fire process temperature curve and maximum temperature distribution plan;

Described detection test routine is:

C) the steel deformation of members was damaged after employing dimensional measurement method was measured fire, steel deformation of members damage after the employing non destructive detection mothod detection of fires;

D) according to fiery density of load, combustible characteristic, be subjected to thermal conduction characteristic, ventilation condition and the fire extinguishing procedure of fiery space envelope wall, determine the fire scene temperature process by adopting the mode that combustion law is inferred and fire disaster simulation software carries out numerical simulation;

G) determine to be subjected to fiery construction material service check by on-site sampling test or the steel of the same race cooling test of heating;

Described data processing structure routine analyzer is:

A) structure fire-response analysis comprises structural response analysis in the fire process and the structural response analysis behind the fire; During according to fire action on the steel construction combination of actual loading carry out structure analysis in the fire process, carry out structure analysis behind the fire according to the steel structure material mechanical property behind the fire, connection status, geometrical shapes variation and deformation of members and damage;

B) numerical simulator of using the steel construction fire performance carries out structural-load-carrying capacity calculating, and wherein established model calculates according to structure and is subjected to fire back present situation;

Described reliability assessment detects with the expert's conclusion program:

According to the every testing result of steel structure member behind the fire, crack defect, metallographic testing result, propose to do focus efforts on special areas and/or technical finesse and/or continue to use suggestion to member;

Described conclusion and processing recommended procedure are:

According to detecting assessment result,, propose as drawing a conclusion and handling suggestion: have a strong impact on suggestion and remove replacing in conjunction with the actual conditions of engineering; Substantially not having influence suggestion reinforcement and strengthening handles; Do not exceed permissible value with distortion, the crack defect vestige is not found in flaw detection, and metallographic no abnormality seen phenomenon can continue to use.